*{
    margin:0;
    padding:0;
    box-sizing: 0;
}
body{
    /* 高度设置，传给父亲 */
    height: 100%;
    background-image: url(./img/1.jpg);
    background-position: center center;
    background-repeat: no-repeat;
    background-size: cover;
}
html{
    /* body的父亲，设置高度 */
    height: 100%;
}
.nav{
    height: 50px;
    background-color: rgba(50, 50, 50, 0.4);
    color: white;
    /* 弹性布局 */
    display: flex;
    justify-content: flex-start;
    align-items: center;
}
.nav img{
    width: 40px;
    height: 40px;
    /* 左边距 */
    margin-left: 30px;
    margin-right: 10px;
    /* 圆形 */
    border-radius: 20px;
}

.nav .spacer{
    /* 占位置 百分比占位置*/
    width: 70%;
}

.nav a{
    /* 去掉下划线 */
    text-decoration: none;
    color: white;
    padding: 0 10px;
}
.container{
    width: 1000px;
    /* 水平居中 */
    margin: 0 auto;
    height: calc(100% - 50px);
    display: flex;
    justify-content: space-between;
}
.container .container-left{
    height: 100%;
    width: 200px;
    margin-right: 10px;
}
.container .container-right{
    height: 100%;
    width: 796px;
    background-color: rgba(255, 255, 255,0.7);
    padding: 10px;
    overflow: auto;
}
.card{
    background-color: rgba(255, 255, 255,0.7);
    /* 内边距 */
    padding: 30px;
    border-radius: 20px;
}
.card img{
    width: 140px;
    height: 140px;
    border-radius: 70px;
}
.card h3{
    text-align: center;
    padding: 10px;
}

.card a{
    /* 默认是行内元素，所以居中不会直接居中 */
    display: block;
    text-align: center;
    color: #555;
    text-decoration: none;
    padding: 10px 0;
}
.card .counter{
    display: flex;
    justify-content: space-around;
    padding: 5px;
}